It is often desirable in consumer and other products to keep separate two or more components of the composition until actual use. Examples of compositions wherein this may be desirable include personal washing compositions wherein cleansing and moisturizing compositions are kept separate prior to application on the skin by the consumer. A patent disclosing such a personal washing composition is Chambers et al., U.S. Pat. No. 5,612,307. Other examples include laundry products wherein it is desirable to keep separate enzyme and bleach, and dental products wherein it may be necessary to isolate peroxide from bicarbonate prior to use of the product. Another application for such containers is to house shampoo in one compartment and conditioner in another.
Numerous patents disclosing dual containers of one sort or another and/or closures have been published. These include Usen et al., U.S. Pat. No. 5,628,429, Hatakeyama et al., U.S. Pat. No. 5,615,803, Blette, U.S. Pat. No. 5,386,928, laia et al., U.S. Pat. No. 5,318,203, Douglas et al., U.S. Pat. No. 5,316,159, O""Meara, U.S. Pat. No. 5,269,441, O""Meara, U.S. Pat. No. 5,244,120, Reil et al., U.S. Pat. No. 5,158,209, De Latorcade, U.S. Pat. No. 5,152,432, Stokes et al., U.S. Pat. No. 5,137,178, Ratclift, U.S. Pat. No. 5,052,590, Pearson et al., U.S. Pat. No. 4,974,756, Gentile U.S. Pat. No. 5,392,947, Mueller U.S. Pat. No. 5,964,539, Gentile U.S. Pat. No. 5,252,312, Gentile U.S. Pat. No. 5,289,949, Gentile U.S. Pat. No. 5,289,950, Abfier et al. U.S. Pat. No. Des. 353,326, Wickham U.S. Pat. No. 5,489,046, Walravens U.S. Pat. No. Des. 329,984 and Meurer et al., U.S. Pat. No. 3,269,389.
A special problem which is encountered in the manufacture of dual containers is that of adhering effectively the containers to each other. Hot melt adhesives are a preferred type of adhesive since they often achieve the best and immediate bonding of the polyolefin material. While hot melt adhesives have the above advantageous characteristics, problems can be encountered with dual containers secured together by a hot melt adhesive, particularly when the containers are subjected to a wide range of temperatures and dynamics during shipping, storage, retail display and use by the consumer.
The invention is directed to a dual container having separately fabricated container chambers which is capable of maintaining its integrity notwithstanding large variations in temperature. In accordance with the invention, the chambers are adhered to each other with at least two different adhesives, preferably two different hot melts. The different adhesives are selected so as to provide maximum adherence at different temperatures, so that the chambers will remain adhered together when experiencing distribution forces over a wide temperature range. For example, in a preferred embodiment of the invention, a stiffer cohesive hot melt, which is more dimensionally stable is placed near the neck and near the bottom of the container. This type of hot melt performs better at higher temperatures and keeps the container assembly in proper alignment. A softer pressure sensitive hot melt may be used in the middle and at the very bottom of the container assembly. The softer hot melt is very tacky and so works well at lower, rather than higher temperatures. At higher temperatures it can become unduly soft and spread. Softer hot melt has good impact resistance.
By using two hot melts, advantage can be taken of their different and complementary advantageous features. This is particularly advantageous since the containers can be subjected to a variety of forces under a variety of conditions, e.g. temperature extremes after manufacture. Thus, by selecting the adhesive in accordance with the invention the containers will be able to endure a given applied force at both temperature extremes (high and low) whereas with a single type adhesive it might only have been able successfully to withstand the stress had it occurred at one of the temperature extremes, e.g. low temperature.
In the case of hot melt, preferably one of the hot melts employed is one which is classified as a pressure sensitive hot melt, which is pliable at room temperature and more impact resistant. It provides superior lower temperature bonding at from 0xc2x0 F. to 40xc2x0 F. A second hot melt preferably is a conventional cohesive hot melt, which is firmer and which provides superior, firmer bonding at temperatures of 70xc2x0 F. to 120xc2x0 F.
In another embodiment, the invention relates to a method for securing together two chambers of a dual chamber container using the two adhesives described above. Indeed, while the invention is described and is particularly applicable to securing together two chambers of a dual chamber container, it may find applicability in other circumstances wherein it is desired to use adhesive to adhere together two objects, particularly where it is desirable to keep the objects secured notwithstanding the possibility of exposure to a wide variety of temperatures. Thus the invention relates to the method of securing such objects and to the objects secured using the two adhesives.
The invention is particularly useful for securing two separate thermoplastic chambers. Adhering the chambers with, for example, two separate hot melt adhesives results in a much stronger bond over a wider temperature range than can be achieved with a single hot melt adhesive.
The invention finds particular application for dispensing two products kept separate prior to application, for example, surfactant and skin benefit agent. Such a container may comprise two chambers, each, having a proximal wall and a distal wall. The chambers are preferably adhered to each other at the proximal wall in accordance with the present invention.
In the further preferred embodiment, the invention is used to secure the chambers of the dual container of Markey et al., U.S. patent application Ser. No. 09/123,296 the disclosure of which is hereby incorporated by reference herein. Although the preferred chambers are essentially identical when viewed from their respective distal walls, they are adhered to each other at an offset so that from any view, both chambers can be seen. This is advantageous in that it permits the consumers to recognize that two separate chambers, and therefore, components, are used notwithstanding the fact that a unitary container is presented. Preferably, the chambers include in their proximal walls complementary raised and recessed portions, eg. protuberances and depressions, which assist the alignment of the chambers in an offset. Likewise, the chambers may be provided with generally longitudinally extending ridges or wedges, which facilitate joining of the chambers in an offset orientation.
Advantageously, the chambers of the container are made of a material which permits the distal walls to be relatively flexible so as to permit a consumer to dispense the product merely by exerting pressure with one hand. A particularly preferred material is medium density polyethylene. In fact, preferably both chambers are made of medium density polyethylene, although softer materials may also be used. Preferably, the ridge disposed on the proximal wall extends in a generally vertical orientation. Preferably aspects of the proximal walls medial to the ridge may be relatively flat, except for raised and recessed portions desirable to align the chambers, in order to permit the chambers to fit readily together. The chambers are adhered together with an adhesive in accordance with the present invention.
An especially preferred alignment scheme comprises a generally vertically extending secondary ridge and a complementary generally vertically extending trough on each of the proximal walls. The adhesives used according to the invention will generally be disposed outside any protuberances or depressions.
Each chamber preferably includes a product exit opening. Typically, the product exit openings lead to a closure.
The closure may include a peripheral flange and a wall extending transversely of the flange and including at least two product egress openings. A closure cover may be attached to the closure base, for example by a hinge. The closure cover may include one or more plugs to assure that product does not escape through the product egress openings when the closure cover is closed.
Both the closure base transverse wall and the closure cover preferably includes one or more drainage openings.
The cover of the closure preferably provides a relatively large surface area so that, if so desired, the container can be conveniently left to stand on the closure.
For even dispensing, it is preferred that the viscosities of the liquids in each chamber be as close as possible to the other.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments and to the accompanying drawings.